# Co-infections with Multiple Viruses: A Frequent cause of Community-Acquired Pneumonia in Sarawak Malaysia

## TL;DR

This study found that many pneumonia patients in Sarawak, Malaysia, had multiple viruses, highlighting the need for better diagnostic methods.

## Contribution

The study reveals the high frequency of viral co-infections in pneumonia patients and the limitations of singleplex assays.

## Key findings

- 24.9% of 441 patients had two or more viruses detected.
- Human rhinoviruses were the most prevalent virus detected.
- Pan-species assays identified 19 additional viruses missed by commercial assays.

## Abstract

•We studied viral causes of pneumonia among hospitalized patients in Sarawak, Malaysia.•110 (24.9%) of the 441 patients had two or more viruses detected.•Having previous contact with sick persons was a risk factor for viral coinfections.•Relying upon a few singleplex molecular assays may mislead clinical staff.

We studied viral causes of pneumonia among hospitalized patients in Sarawak, Malaysia.

110 (24.9%) of the 441 patients had two or more viruses detected.

Having previous contact with sick persons was a risk factor for viral coinfections.

Relying upon a few singleplex molecular assays may mislead clinical staff.

Equatorial Sarawak, Malaysia, has been the site of important novel respiratory virus detections. During the COVID-19 pandemic, we sought to determine viral causes of pneumonia that were not SARS-CoV-2.

Using an informed consent process, we enrolled patients from four hospitals in Sarawak for this cross-sectional study. Patients permitted a nasopharyngeal (NP) swab collection and completed a risk factor questionnaire. We studied NP swabs with molecular diagnostics for previously recognized respiratory viruses such as influenza A and D viruses, and pan-species assays for adenoviruses, coronaviruses, enteroviruses, pneumoviruses, and paramyxoviruses.

Among 441 patients, 78.2% had at least one virus detected, and 24.9% had multiple viruses detected. Among the viruses detected, a commercial multiplexing assay found the most prevalent detections were human rhinoviruses (43.1%), respiratory syncytial virus (18.6%), human metapneumovirus (8.6%), influenza A (7%), adenovirus (6.1%), and influenza B (5.6%). However, the pan-species assays detected evidence of 19 additional respiratory viruses that the commercial multiplexing assay missed.

Patients with pneumonia in this hot and humid region often had evidence of multiple viral infections, especially children under 5 years old. Clinicians who rely on singleplex molecular assays for prevalent viruses such as influenza A, SARS-CoV-2, and respiratory syncytial virus may miss other important viral causes of illness in such patients.

Image, graphical abstract